High output concentrator

ABSTRACT

A multi-chamber canister for a pressure swing absorption system within a general housing assembly. The chambers include a first molecular sieve chamber for receiving a first molecular sieve for separating air from the ambient environment into a concentrated gas and at least a second molecular sieve chamber disposed within the housing assembly for receiving a second molecular sieve for separating air from the ambient environment into a concentrated gas component. Furthermore, a supply chamber is disposed within the housing for receiving air from the ambient environment and for communicating air to either first or second molecular sieve chambers.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation under 35 U.S.C. §120/121 of U.S.patent application Ser. No. 11/698,682, filed Jan. 26, 2007, which is aDivisional of U.S. patent application Ser. No. 10/935,733, filed Sep. 7,2004, now U.S. Pat. No. 7,429,289, granted Sep. 30, 2008.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a pressure swing absorption chamber, and moreparticularly to an oxygen concentrator system having a multi-chambercanister for receiving compressed air from a compressor and directingthe air through a series of chambers integral within a single assemblyfor producing concentrated oxygen in a pressure swing absorption system,which system provides 10 LPM at an oxygen concentration of at least 93%.

2. Description of the Related Art

Adsorption separation processes depend on the ability of certain solidsto selectively adsorb one or more components from a gaseous mixture. Inoxygen concentrators for patient use, the adsorption separationprocesses are usually fixed bed operations, including two main steps,the adsorption step and the desorption step.

Pressure Swing Adsorption (PSA) is a useful technique for separatingcomponents of gaseous mixtures in such medical uses. A gaseous mixture,typically ambient air, is fed into a chamber, where the species areseparated, producing a stream with a high percentage of one component.Air contains many species, namely approximately 21% oxygen, 78%nitrogen, 0.9% argon and 0.1% other trace gases. PSA can be used toseparate the oxygen from the inlet air, to supply the patient withhigher concentrations of oxygen.

Generally, such species separation in the chamber is achieved by using azeolite, or molecular sieve, which has a selective affinity foradsorbing a certain component in the mixture. Zeolites are natural orsynthetically produced molecular sieves that have uniform pores orcrystalline cavities. Chemical species small enough to fit into thezeolite's pores are adsorbed onto the surface of the zeolite material.How readily a species adsorbs onto the zeolite depends on the shape andsize of the molecule compared to the shape and size of the pores in thezeolite pellet. A zeolite can adsorb a molecule of any diameter up toits own pore size.

Pressure Swing Adsorption relies on swings in pressure to cycle thechamber sequentially from selective adsorption to desorption. This swingcan occur from high pressure to atmospheric pressure or from atmosphericpressure to vacuum. If the swing occurs from atmospheric pressure tovacuum, it is technically considered Vacuum Pressure Swing Adsorption(VPSA). It is well know to those of skill in the art the PSA and VPSAtechniques for species separation are quite different, each techniquewith its own attendant benefits and deficiencies.

A typical pressure swing absorption system is an oxygen concentratorthat separates the oxygen from air for subsequent inhalation by apatient. Conventional systems provide 5 liters per minute (LPM). Suchoxygen concentrators include a plurality of molecular sieve beds forseparating the gas into an oxygen and a nitrogen fraction whereby theoxygen is subsequently provided to a patient while the nitrogen isretained in the sieve bed and subsequently purged. These oxygenconcentrators include several components such as an air compressor, twothree-way air valves, multiple canisters each housing a separatemolecular sieve and a product reservoir tank. Such structures requireextensive valving and plumbing which affects the efficiency and costs ofthese systems.

U.S. Pat. No. 5,997,617 to Czabala et al. discloses an improvement inthe art of 5 LPM pressure swing absorption system that incorporates amulti-chamber canister assembly for improving both the efficiency of thesystem, and the cost of the system. The assembly minimizes thetemperature difference between molecular sieves due to their locationwithin the canister, and provides a system wherein multiple operationsof the pressure swing absorption system are incorporated within a singlehousing assembly.

The Czabala et al. PSA system includes a multi-chamber canister for apressure swing absorption system which includes at least three chambers.The canister includes a housing of a general length. A first molecularsieve chamber is disposed within the housing for receiving a firstmolecular sieve for separating air from the ambient environment into aconcentrated gas component. At least a second molecular sieve-chamber isalso disposed within the housing for receiving a second molecular sievefor separating air from the ambient environment into a concentrated gascomponent. A supply chamber is disposed within the housing for receivingair from the ambient environment and for communicating the air to eitherthe first or second molecular sieve chamber.

When those of skill in the art approach the problem of “scaling-up” aCzabala et al.-like device to deliver in the range of 10 LPM, they have,prior to the present invention, simply attempted to design such systemswith double the sieve material, and double the air flow, to providedouble the resulting 5 LPM of oxygen. Yet, the additional sieve materialweight and volume in such an approach results in a device of a size andweight that is disadvantageous not only to the market, but to thepatient as well in view of price, noise, size, weight and powerconsumption.

An example of such a device is the INTEGRA_(TEN)™ by SeQual. Thisconcentrator is marketed as a 10 LPM, but suffers from basically adoubling of SeQual's LPM unit. Further, it utilizes at least twelveindividual chambers, sequentially directing the flow of compressed airto a group of four sieve beds (adsorption), while at the same timeanother four beds are purged into the atmosphere through the valve(desorption). The remaining four of the twelve beds are interconnectedthrough the valve to equalize pressure as the sieve beds sequentiallytransition between adsorption and desorption. Thus, not only does theunit have an overabundance of chambers, it is nearly twice the weight,nearly twice the size, and uses nearly twice the adsorbent material ofthe 5 LPM device to provide up to 10 LPM. Further, the oxygenconcentration from ½ to 7 LPM is only 93.5% (+/−1.5%), and from 7 to 10LPM is only 92% (+/−3%).

The INTEGRA_(TEN)™ has some disadvantageous specific performance ratios.For example, the INTEGRA_(TEN)™ is 4.22 ft³, and thus has a specificunit size per LPM=0.422 ft³/LBM when providing 10 LPM. Further, thisunit has a weight of 57 lbs, and thus has a specific unit weight perLPM=5.7 lbs/LBM when providing 10 LPM.

Thus, while the Czabala et al. system is beneficial, and is efficient inthe 5 LPM range of operation, and the INTEGRA_(TEN)™ by SeQual providesup to 10 LPM in a scaled-up version of their 5 LPM unit, it would bedesirable to provide a PSA system that could deliver high output in therange of 10 LPM in a two chamber system, and deliver a reliable oxygenconcentration of 93% or more at 10 LPM, all in a system that has similarweight, size, sound level and power consumption characteristics as theCzabala et al. system. It is to such an oxygen concentration system thatthe present invention is primarily directed.

SUMMARY OF THE INVENTION

Briefly described, in its preferred form, the present system is arelatively light weight, small size, low sound level, low powerconsumption PSA oxygen concentrator with an output in the range of 10LPM. The system is an improvement over the prior art, and can providethe beneficial characteristics of a 10 LPM system in a compact devicewith its use of, among other improvements, a highly adsorbent molecularsieve, and a high flow compressor that is matched to the 10 LPM outputand the higher performance molecular sieve.

The present invention, illustrated under the column of TABLE 1 labeled“Respironics 10” has many beneficial performance ratios over theconventional 5 LPM devices, and the 10 LPM device of INTEGRA_(TEN)™ bySeQual, under the column of TABLE1 labeled “Sequal 10”.

It is clear from the concentrator comparisons of TABLE 1 that thepresent invention provides superior performance over the conventionaldevices, and embodies specific performance ratios that distinguish itfrom the prior art. Many of the identified concentrators of TABLE 1while perhaps exhibiting some beneficial ratios, are in fact less than10 LPM systems, as distinguishable from the present system.

Namely, the present invention is an absorption system for separating airinto a concentrated gas component, including an air supply, a compressorfor receiving and compressing the air supply, providing a compressed airsupply, molecular sieve material for separating the compressed airsupply into a concentrated gas component; and an outlet delivering atleast 10 liters per minute (LPM) of concentrated gas component from themolecular sieve material.

The present 10 LPM system preferably has at least one of the followingbeneficial performance ratios:

a specific total weight per LPM<5.7 lbs/LBM;

a specific total molecular sieve material weight per LPM≦1 lbs/LBM;

a specific volume per LPM<0.422 ft³/LBM;

a specific sound level per LPM≦10 dBA/LBM; and/or

a specific power level per LPM≦120 W/LBM.

In one preferred embodiment, the present invention is a pressure swingabsorption system having five or less molecular sieve beds forseparating air into an oxygen and a nitrogen fraction whereby the oxygenis subsequently provided to a patient while the nitrogen is retained inthe sieve bed and subsequently purged, wherein the recovery rate isgreater than approximately 30% (O_(2 OUT)/O_(2 IN)). In anotherpreferred embodiment, the system has two beds.

In another preferred embodiment, the present invention comprises amaintenance free SMC® “sure cycle” valve, designed specifically for thepresent invention, has an Optional Oxygen Percentage Indicator (OPI®)that ultrasonically measures oxygen output as a purity indication, hasprotective tubing neatly guarding the electrical wires and tubing—thatis a double fault against electric shock, has an integrated sievecanister that reduces tubing connections to enhance bed life, has a twinhead compressor (higher stroke for more airflow through sieve beds), hasa smooth bottom making cleaning the cabinet easier, and has highlydurable casters designed to withstand rigorous usage.

Preferred specifications of the present invention include:

Flow Rate 10 LPM in 1 liter increments Electrical Requirements 120 V/60Hz (±10%) Oxygen Percentage Indicator Green Light Normal greater than82% Yellow Light between 70-82% Red Light Less than 70% OxygenConcentration 92 ± 4% @ 8-10 LPM 94 ± 2% @ 3-7 LPM 92 ± 4% @ 1-2 LPMWeight 53 ± .5 lbs Dimensions 27″ × 19″ × 13″ Storage/transportTemperature −30 to 160° F. Operating Temperature 55-90° F.Storage/transport Humidity Up to 95%, non-condensing Operating Pressure10-30 psig Alarm Indicators High system pressure Low system pressurePower failure Low oxygen level No oxygen flow

These and other objects, features and advantages of the presentinvention will become more apparent upon reading the followingspecification in conjunction with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a pressure swing absorption systemaccording to an embodiment of the present invention.

FIG. 2 is an exploded view of a pressure swing absorption systemaccording to an embodiment of the present invention.

FIG. 3 is a perspective view of a multi-chamber canister for use in apressure swing absorption system according to an embodiment of thepresent invention.

FIG. 4 a is a perspective view of a top cover for communicating fluidflow within a multi-chamber canister for use in a pressure swingabsorption system according to an embodiment of the present invention.

FIG. 4 b is a perspective view of a top cover for communicating fluidflow within a multi-chamber canister for use in a pressure swingabsorption system according to an embodiment of the present invention.

FIG. 5 is a perspective view of a bottom cover for communicating fluidflow within a multi-chamber canister for use in a pressure swingabsorption system according to an embodiment of the present invention.

FIG. 6 is a perspective view of a valving system for communicating fluidflow within a multi-chamber canister for use in a pressure swingabsorption system according to an embodiment of the present invention.

FIG. 7 is a graph of the O₂ output of the concentrators of TABLE 1.

FIG. 8 is a graph of the weight of the concentrators of TABLE 1.

FIG. 9 is a graph of the size of the concentrators of TABLE 1.

FIG. 10 is a graph of the sound levels of the concentrators of TABLE 1.

FIG. 11 is a graph of the power consumption of the concentrators ofTABLE 1.

FIG. 12 is a graph of the specific unit weight versus LPM of theconcentrators of TABLE 1.

FIG. 13 is a graph of the specific size versus LPM of the concentratorsof TABLE 1.

FIG. 14 is a graph of the specific sound level versus LPM of theconcentrators of TABLE 1.

FIG. 15 is a graph of the specific power versus LPM of the concentratorsof TABLE 1.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

Referring now in detail to the drawing figures, wherein like referencenumerals represent like parts throughout the several views, FIGS. 1 and3 illustrate a pressure swing absorption system 8 including a compressor10 having an inlet for receiving air from the ambient environment.Compressor 10 compresses the air and provides the pressurized air tomulti-chamber canister 12. In the preferred embodiment, the presentpressure swing absorption system 8 fractionalizes oxygen from the air inan oxygen concentration system. The operation and design of oxygenconcentration systems are described in U.S. Pat. Nos. 5,183,483 and5,997,617, both of which are hereby incorporated by reference.

Compressor 10 is preferably a high flow compressor that is oiless, andcooperative with the high output range of 10 LPM. A twin-head compressorcan be used.

Multi-chamber canister 12 includes multiple chambers for producingconcentrated oxygen from pressurized air. Canister 12 is preferably acylindrical elongated housing providing sufficient volume for therespective chambers. In the preferred embodiment, canister 12 is asingle extrusion, but can comprise of separate housings interconnectedfor forming a canister assembly. Supply chamber 14 receives thepressurized air from the compressor for delivery to the molecularsieves. First molecular sieve chamber 16 is located adjacent to secondmolecular sieve chamber 18 which house zeolite or other suitablematerial for fractionating air into oxygen and a waste product gas suchas nitrogen.

Zeolites are highly crystalline alumino-silicate frameworks comprising[SiO₄]⁴⁻ and [AlO₄]⁵⁻ tetrahedral units. T atoms (Si, Al) are joined byan oxygen bridges. Introduction of an overall negative surface chargerequires counter ions e.g. Na⁺, K⁺, and Ca²⁺. The zeolite crystalscontain water, and as the water is driven off by heating, there is nodiscernible collapse of the framework structure. This leads to a highlycrystalline, microporous adsorbent that has an internal structure whichcan be easily tailored to adsorb any number of species.

Zeolites have beneficial molecular sieving properties. The pore sizedistribution can be modified, enabling the zeolite to be used as aso-called molecular sieve. Molecules which are too large to diffuse intothe pores are excluded, whereas molecules which have a kinetic diametersmaller than the pore size, diffuse into the pores, adsorb and undercertain conditions are capable of undergoing catalytic reactions. Anexample of this is in the sieving of straight and branched chainedhydrocarbons to increase the octane number of gasoline.

In order to enable the present system to deliver a relatively lightweight, small size, low sound level, low power consumption PSA oxygenconcentrator with an output in the range of 10 LPM, a highly adsorbentmolecular sieve preferably is employed. SILIPORITE® Molecular Sieves aremineral synthetic products (zeolites) with remarkable selectiveadsorption properties, and are an example of a preferable material forfractionating air into oxygen and a waste product gas such as nitrogenfor use with the present system.

ATOFINA Chemicals, Inc. distributes and provides technical services forSILIPORITE® Molecular Sieves for its sister company, CECA S. A. BothNitroxy 5 and Nitroxy 51 in the SILIPORITE® line are beneficial.

First molecular sieve chamber 16 and second molecular sieve chamber 18have abutting walls 20 and 22 to maintain a constant temperature betweenthe chambers which reduces the swing in oxygen concentration between thetwo chambers. Product chamber 24 is in fluid communication with bothfirst molecular sieve chamber 16 and second molecular sieve chamber 18for receiving and storing concentrated oxygen produced by the respectivesieves. Exhaust chamber 26 is in fluid communication with both first andsecond molecular sieve chambers 16 and 18 and receives the waste productgas which has been purged from a respective molecular sieve. Each ofthese chambers extends along the length of multi-chamber canister 12.

As shown in FIG. 3, multi-chamber canister 12 is preferably designed asa single extruded unit having a single canister housing wall 130 withall of the respective chambers defined within housing wall 130. Firstmolecular sieve chamber 16 is defined by first molecular sieve chamberpartition 132 interfacing with canister housing wall 130. Firstmolecular sieve chamber partition 132 has a first end and a second endwhich interface with canister wall 130. An intermediary portion of firstmolecular sieve chamber partition 134 is offset from canister wall 130to assist in defining first molecular sieve chamber 16. Like firstmolecular sieve chamber 16, second molecular sieve chamber 18 is definedby second molecular sieve chamber partition 136 interfacing withcanister housing wall 130. Second molecular sieve chamber partition 136has a first end and a second end which interface with canister wall 130.An intermediary portion of second molecular sieve chamber partition 138is offset from canister wall 130 to assist in defining second molecularsieve chamber 18. In the preferred embodiment, intermediary portions 134and 138 respectively abut each other to maintain a consistenttemperature between the two molecular sieve beds.

As further shown in FIG. 3, supply chamber 14 is defined withinmulti-chamber canister 12 by supply chamber partition 140 being offsetfrom canister housing wall 130. Exhaust chamber 26 can be defined by itsown exhaust chamber partition, or as shown in FIG. 3 as one embodiment,defined by the offsets of first and second molecular sieve partitions132 and 136 in combination with the offset of supply chamber partition140. Likewise, product chamber 24 can be defined by its own productchamber partition being offset from canister housing wall 130, or as oneembodiment, defined by the offsets of first and second molecular sievepartitions 132 and 136 in combination with an offset with canisterhousing wall 130. Each of the respective partitions extends along thelength of multi-chamber canister 12. It is understood that severalchamber configurations can be had within the housing and that aparticular chamber can be defined either by its own particular partitionor as an offset between two other partitions.

An exploded view of the multi-chamber canister assembly is shown in FIG.2. Top portion 28 of multi-chamber canister 12 carries a top cover 30.Top cover 30 encloses the top portion of the respective chambers ofmulti-chamber canister 12 and includes a plurality of orifices enablingfluid flow between the respective chambers which will be described inmore detail hereinafter. Valve 32 directs the communication of fluidflow between the orifices of top cover 30 and the respective chambers ofmulti-chamber canister 12. Top cover seal 34 seals the connectionbetween top cover 30 and multi-chamber canister 12. Pressure regulator36 regulates the pressure of concentrated oxygen delivered from productchamber 24 to a patient. The bottom portion 38 of multi-chamber canister12 carries bottom cover 40. Bottom cover 40 encloses the bottom of therespective chambers of multi-chamber canister 12 and provides for fluidcommunication between the respective chambers as will be described inmore detail hereinafter. Bottom cover seal 42 seals the connectionbetween bottom cover 40 and multi-chamber canister 12.

Top cover 30 is shown in more detail in FIGS. 4 a and 4 b and includesvalve seat 44. Top cover 30 includes first molecular sieve cover plenum46 and second molecular sieve cover plenum 48. Disposed within firstmolecular sieve cover plenum 46 at a point which aligns with valve seat44 is first molecular sieve inlet port 50 which will provide fluidcommunication with first molecular sieve 16. Disposed within secondmolecular sieve cover plenum 48 at a point which aligns with valve seat44 is second molecular sieve inlet port 52 which will provide fluidcommunication with second molecular sieve 18. Top cover 30 also includesexhaust port 54 which communicates with exhaust chamber 26 to permitventing of waste product gas from the system. Furthermore, disposedwithin top cover 30 is supply port 56 which communicates with supplychamber 14. Springs 58 are carried by top cover 30 for maintaining themolecular sieve zeolite material in place within the respectivemolecular sieve chambers.

Valve seat 44 includes various ports which correspond with theaforementioned ports of top cover 30 for communicating fluid flowthroughout the pressure swing absorption cycle. Valve seat firstmolecular sieve port 60 communicates with first molecular sieve port 50,valve seat second molecular sieve port 62 communicates with secondmolecular sieve port 52, valve seat exhaust port 64 communicates withexhaust port 54 and valve seat supply port 66 communicates with supplyport 56. Valve 32 is carried by valve seat 44 for directing fluid flowbetween the respective ports during operation of the pressure swingabsorption system.

FIG. 5 illustrates bottom cover 40 which controls flow between therespective molecular sieves 16 and 18 during the purging cycle and alsocontrols the delivery of product gas from the respective molecularsieves to product chamber 24. Bottom cover 40 includes first molecularsieve bottom cover plenum 67, second molecular sieve bottom cover plenum68, supply chamber bottom plenum 70, exhaust chamber outlet port 72, andproduct tank bottom plenum 74. Bottom cover 40 includes cavities suchthat the respective chambers are defined by multi-chamber canister 12 incombination with bottom cover 40. For example, bottom cover 40 includesfirst molecular sieve chamber bottom wall 76, second molecular sievechamber bottom wall 78, product tank bottom wall 80 and supply chamberbottom wall 82. The combination of the bottom walls and plenums enclosethe respective chambers of multi-chamber canister 12.

The delivery of product gas to product chamber 24 from the respectivemolecular sieves is controlled in part by delivery system 84. Deliverysystem 84 includes first gas outlet port 86 defined within firstmolecular sieve chamber bottom wall 76 and second gas outlet port 88defined within second molecular sieve chamber bottom wall 78. First gasoutlet port 86 communicates with first delivery channel 90 andterminates at first internal gas outlet port 92 which is located withinproduct chamber 24 for delivering concentrated oxygen from firstmolecular sieve chamber 16 to product chamber 24. Second gas outlet port88 communicates with second delivery channel 94 and terminates at secondinternal outlet port 96 for delivering concentrated oxygen from secondmolecular sieve chamber 18 to product chamber 24. Dual check valve 98overlies both first and second internal gas outlet ports 86 and 96. Bothfirst and second internal gas outlet ports 86 and 96 will communicatewith product chamber 24 when open. In the preferred embodiment, firstand second internal gas outlet ports 86 and 96 and dual check valve 98are located within supply chamber 24. Check valve retainer 100 maintainspressure on dual check valve 98 to close off first and second internalgas outlet ports 86 and 96 preventing a backflow of product gas to arespective molecular sieve ensuring that the product gas is delivered toproduct chamber 24.

During the purging cycle of each molecular sieve, purge control orifice102 communicates pressurized gas from a molecular sieve which isundergoing a charging cycle to the other molecular sieve. Purge controlorifice 102 extends through the abutting walls of first and secondmolecular sieve chambers 16 and 18. In the preferred embodiment,multi-chamber canister 12 is a single extrusion such that first andsecond molecular sieve chambers 16 and 18 share common wall 104,however, multi-chamber canister 12 can be comprised of an assembly ofseparate chambers integrated to form a multi-chamber assembly. In thissituation, common wall 104 will comprise of separate molecular sievechamber walls which abut. This design assists in maintaining an eventemperature between the molecular sieves which enables the concentrationof oxygen produced by each respective sieve to be approximately equal inconcentration level.

Compressed air inlet 106 receives compressed air from a compressor andcommunicates the gas to supply chamber 14 through supply port 108bypassing second molecular sieve chamber 18. As shown in FIG. 1 sincethe compressed air is received at the bottom of multi-chamber canisterassembly 12, the compressed air must travel along the length of thecanister to reach valve 32 for subsequent presentation to either firstor second molecular sieve chambers 16 or 18. By requiring the compressedair to travel along the length of canister 12, the external wall ofcanister 12 functions as a heat exchanger for cooling the compressedair. Generally, air after compression is at a higher temperature thanambient. The effectiveness of the molecular sieves is increased with airat a cooler temperature. Accordingly, the cooling of the compressed airprior to entry into the molecular sieves enhances the efficiency of thepressure swing absorption system.

As shown in FIG. 4 a, top cover 30 includes supply chamber top cavity110 which encloses the top portion of supply chamber 24 of multi-chambercanister 12. Product supply port 112 communicates the concentrated gasto a patient through pressure regulator 36. Product chamber pressuresensor tap 114 enables the mounting of a pressure sensor for determiningthe pressure within product chamber 24.

FIG. 6 illustrates valve 32. Valve 32 is carried by valve seat 44 forcommunicating the flow of fluid throughout the pressure swing absorptioncycle. Valve inlet port 116 opens and closes for communicatingcompressed air from supply chamber 14 to molecular sieve chambers 16 and18. First molecular sieve valve outlet 118 and second molecular sievevalve outlet 120 open and close to permit compressed air to enter therespective molecular sieves during operation of the pressure swingabsorption cycle. Valve exhaust outlet 122 communicates with exhaustchamber 26 permitting purged gas to exit the respective molecular sievesand enter exhaust chamber 26 for venting through exhaust port 72. Valve32 is controlled by a microprocessor and solenoids, not shown, fordirecting communication of fluid throughout the system.

When assembled as shown in FIG. 1, top and bottom covers 30 and 40 incombination with multi-chamber canister 12 define a fully integratedsystem wherein a supply chamber, product chamber, exhaust chamber andfirst and second molecular sieve chambers are enclosed within a generalprofile defined by multi-chamber canister 12. As previously mentioned,multi-chamber canister can be a single extrusion or a plurality ofextrusions wherein the chambers are configured to be enclosed withinseparate extrusions and wherein the plurality of extrusions areassembled to define a configuration similar to that shown in FIG. 1.

In operation, air enters compressor 10 and is compressed resulting inthe compressed air having a temperature higher than the ambient air. Thecompressed air enters multi-chamber canister 12 through bottom cover 40and is presented to supply chamber 14. The compressed air is passedthrough supply chamber 14 to valve 32 for delivery to a respectivemolecular sieve chamber 16 or 18. Since valve 32 is located on oppositeends of multi-chamber canister 12, the compressed air travels along thelength of multi-chamber canister 12 enabling multi-chamber canister 12to act as a heat exchanger for cooling the compressed air prior todelivery to a respective molecular sieve. Valve 32 opens a respectivemolecular sieve chamber enabling the compressed air to enter themolecular sieve chamber. The molecular sieve material filters thenitrogen molecules from the air producing a concentration of oxygen. Theconcentrated oxygen in turn pressurizes a respective outlet port 86 or88 which forces check valve retainer 100 to bend, opening up dual checkvalve 98 enabling the concentrated oxygen to enter product chamber 24,while simultaneously maintaining the other respective outlet port closedpreventing a backflow of concentrated oxygen to flow into the otherrespective molecular sieve. The concentrated oxygen passes along thelength of multi-chamber canister and exists through pressure regulator36. Once again, the passage of the concentrated oxygen along the lengthof multi-chamber canister 12 enables multi-chamber canister 12 to act asa heat exchanger for cooling the concentrated oxygen prior to deliveryto a patient.

Approximately one third of the concentrated oxygen enters productchamber 24 allowing the remaining two thirds to enter the othermolecular sieve chamber through purge control orifice 102. Valve 32simultaneously opens exhaust port 54 enabling nitrogen to be purged fromthe respective molecular sieve chamber and pass through exhaust port 54in top cover 30 and enter into exhaust chamber 26 for subsequent ventingat exhaust chamber outlet port 72 located in bottom cover 40. The cycleof charging and purging of the molecular sieves is further detailed inU.S. Pat. No. 5,183,483.

The present system thus provides a 10 LPM output in a unit havingapproximately the same size, weight, sound level and power consumptionas a standard 5 LPM model. Preferable system characteristics for thepresent invention include an output of 10 LPM at 95% O₂, a sieve weightof 5.4 lbs, a unit weight of 53.5 lbs, a unit size of 26.8″×18.9″×13.3″(a volume of 6737 in³, or 3.9 ft³), a sound level at 1 m×1 m of 50 dBA,and a specific power of 600 W.

The present invention includes the provision of a high outputconcentrator that illustrates an advancement in technology when viewedunder specific performance ratios, ratios unmet in the current art. Thepresent invention has a specific unit weight per LPM<5.7 (preferably,for example, 53.5 lbs per 10 LPM=5.35 lbs/LBM). The present inventionhas a specific sieve weight per LPM≦1 (preferably, for example, 5.4 lbsper 10 LPM=0.54 lbs/LBM). The present invention has a specific unit sizeper LPM<0.42 (preferably, for example, 3.9 ft³ per 10 LPM=0.39 ft³/LBM).The present invention has a specific sound level per LPM≦10 (preferably,for example, 50 dBA per 10 LPM=5 dBA/LBM). Lastly, the present inventionhas a specific power level per LPM≦120 (preferably, for example, 600 Wper 10 LPM=60 W/LBM).

FIGS. 7-15 illustrate graphically many of the performancecharacteristics provided in TABLE 1.

The design of the present system, with its use of the improvedcompressor and adsorbent material over the prior art designs, not onlyprovides a compact unit for the delivery of 10 LPM, but further deliversa reliable oxygen concentration of 93% or more at 10 LPM.

The present system further utilizes shorter cycle times that present 10LPM systems. Cycle time refers to the time taken for the completion ofone adsorption-desorption cycle, which in turn decides the productivity(amount of product produced per unit mass of the adsorbent per unittime) of the process. Hence, shorter cycle times translate into higherproductivity.

While the invention has been disclosed in its preferred forms, it willbe apparent to those skilled in the art that many modifications,additions, and deletions can be made therein without departing from thespirit and scope of the invention and its equivalents as set forth inthe following claims.

1. An absorption system for separating air into a concentrated gascomponent, said system comprising: an air supply; a compressor forreceiving and compressing the air supply, providing a compressed airsupply; molecular sieve material for separating the compressed airsupply into a concentrated gas component; and an outlet delivering atleast 10 liters per minute (LPM) of concentrated gas component from themolecular sieve material; wherein the system has total volume; andwherein the system has a specific volume per LPM≦0.42 ft³/LBM.
 2. Thesystem of claim 1, wherein the system comprises a pressure swingadsorption system.
 3. The system of claim 1, wherein the molecular sievematerial is a SILIPORITE® molecular sieve material.
 4. The system ofclaim 3, wherein the molecular sieve material is housed in two molecularsieve chambers.
 5. The system of claim 4, further comprising: a housingof a general length including a housing wall; a first molecular sievechamber defined within said housing for receiving the molecular sievematerial, the first molecular sieve chamber defined by a first molecularsieve chamber partition, wherein the first molecular sieve chamberpartition and the housing wall define the first molecular sieve chamber;at least a second molecular sieve chamber defined within said housingfor receiving the molecular sieve material, the second molecular sievechamber defined by a second molecular sieve chamber partition, whereinthe second molecular sieve chamber partition and the housing wall definethe second molecular sieve chamber; and a supply chamber defined withinthe housing for receiving the compressed air supply and forcommunicating the compressed air supply to the first and the secondmolecular sieve chambers, the supply chamber defined by a supply chamberpartition, wherein the supply chamber partition and the housing walldefine the supply chamber, and wherein the supply chamber extends alonga general length of the housing, the supply chamber including an airinlet for the air supply, the air inlet disposed a general distanceapart from where the supply chamber fluidly communicates with either oneof the first and the second molecular sieve chambers enabling thehousing to act as a heat exchanger for cooling the air supply receivedfrom the air inlet.